krzysztofsurdy/django-components

Django Components

Complete reference for all 33 Django components - patterns, APIs, configuration, and best practices for Python 3.10+ and Django 6.0.

Component Index

Models & Database

• Models - Model definition, field types, Meta options, inheritance, managers -> reference
• QuerySets - QuerySet API, field lookups, Q objects, F expressions, aggregation -> reference
• Migrations - Migration workflow, operations, data migrations, squashing -> reference
• Database Functions - Database functions, conditional expressions, full-text search -> reference

Views & HTTP

• Views - Function-based views, shortcuts (render, redirect, get_object_or_404) -> reference
• Class-Based Views - ListView, DetailView, CreateView, UpdateView, DeleteView, mixins -> reference
• URL Routing - URL configuration, path(), re_path(), namespaces, reverse() -> reference
• Middleware - Middleware architecture, built-in middleware, custom middleware -> reference
• Request & Response - HttpRequest, HttpResponse, JsonResponse, StreamingHttpResponse -> reference

Templates

• Templates - Template language, tags, filters, inheritance, custom template tags -> reference

Forms

• Forms - Form class, fields, widgets, ModelForm, formsets, validation -> reference

Admin

• Admin - ModelAdmin, list_display, fieldsets, inlines, actions, customization -> reference

Authentication & Security

• Authentication - User model, login/logout, permissions, groups, custom user models -> reference
• Security - CSRF, XSS, clickjacking, SSL, CSP, cryptographic signing -> reference
• Sessions - Session framework, backends, configuration -> reference

Caching

• Cache - Cache backends (Redis, Memcached, DB, filesystem), per-view/template caching -> reference

Signals

• Signals - Signal dispatcher, built-in signals (pre_save, post_save, etc.) -> reference

Communication

• Email - send_mail, EmailMessage, HTML emails, backends -> reference
• Messages - Messages framework, levels, storage backends -> reference

Testing

• Testing - TestCase, Client, assertions, RequestFactory, fixtures -> reference

Files & Static Assets

• Files - File objects, storage API, file uploads, custom storage -> reference
• Static Files - Static file configuration, collectstatic, ManifestStaticFilesStorage -> reference

Internationalization

• I18n - Translation, localization, timezones, message files -> reference

Serialization & Data

• Serialization - Serializers, JSON/XML formats, natural keys, fixtures -> reference
• Content Types - ContentType model, generic relations -> reference
• Validators - Built-in validators, custom validators -> reference
• Pagination - Paginator, Page objects, template integration -> reference

Async & Tasks

• Async - Async views, async ORM, sync_to_async, ASGI -> reference
• Tasks - Tasks framework, task backends, scheduling -> reference

Configuration & CLI

• Settings - Settings reference by category, splitting settings -> reference
• Management Commands - Built-in commands, custom commands, call_command -> reference
• Logging - Logging configuration, handlers, Django loggers -> reference

Deployment

• Deployment - WSGI, ASGI, Gunicorn, Uvicorn, static files, checklist -> reference

Quick Patterns

Define a Model

from django.db import models

class Article(models.Model):
    title = models.CharField(max_length=200)
    slug = models.SlugField(unique=True)
    content = models.TextField()
    published = models.BooleanField(default=False)
    created_at = models.DateTimeField(auto_now_add=True)
    author = models.ForeignKey('auth.User', on_delete=models.CASCADE)

    class Meta:
        ordering = ['-created_at']

    def __str__(self):
        return self.title

Define a URL + View

# urls.py
from django.urls import path
from . import views

urlpatterns = [
    path('articles/<int:pk>/', views.article_detail, name='article_detail'),
]

# views.py
from django.shortcuts import render, get_object_or_404

def article_detail(request, pk):
    article = get_object_or_404(Article, pk=pk)
    return render(request, 'articles/detail.html', {'article': article})

Class-Based View

from django.views.generic import ListView, DetailView

class ArticleListView(ListView):
    model = Article
    queryset = Article.objects.filter(published=True)
    paginate_by = 20

class ArticleDetailView(DetailView):
    model = Article
    slug_field = 'slug'

QuerySet Filtering

from django.db.models import Q, F, Count

# Complex filtering
articles = Article.objects.filter(
    Q(title__icontains='django') | Q(content__icontains='django'),
    published=True,
).exclude(
    author__is_active=False
).annotate(
    comment_count=Count('comments')
).order_by('-created_at')

Form with Validation

from django import forms

class ArticleForm(forms.ModelForm):
    class Meta:
        model = Article
        fields = ['title', 'slug', 'content', 'published']

    def clean_title(self):
        title = self.cleaned_data['title']
        if len(title) < 5:
            raise forms.ValidationError('Title must be at least 5 characters.')
        return title

Cache a View

from django.views.decorators.cache import cache_page

@cache_page(60 * 15)  # 15 minutes
def article_list(request):
    articles = Article.objects.filter(published=True)
    return render(request, 'articles/list.html', {'articles': articles})

Signal Receiver

from django.db.models.signals import post_save
from django.dispatch import receiver

@receiver(post_save, sender=Article)
def notify_on_publish(sender, instance, created, **kwargs):
    if instance.published and created:
        send_notification(instance)

Management Command

from django.core.management.base import BaseCommand

class Command(BaseCommand):
    help = 'Process pending articles'

    def add_arguments(self, parser):
        parser.add_argument('--limit', type=int, default=100)

    def handle(self, *args, **options):
        count = process_articles(limit=options['limit'])
        self.stdout.write(self.style.SUCCESS(f'Processed {count} articles'))

Test Case

from django.test import TestCase

class ArticleTests(TestCase):
    def setUp(self):
        self.article = Article.objects.create(
            title='Test Article',
            slug='test-article',
            content='Content here',
            published=True,
        )

    def test_article_detail_view(self):
        response = self.client.get(f'/articles/{self.article.pk}/')
        self.assertEqual(response.status_code, 200)
        self.assertContains(response, 'Test Article')

Best Practices

• Target Python 3.10+ and Django 6.0 with type hints where helpful
• Use class-based views for CRUD; function-based views for custom logic
• Prefer select_related/prefetch_related to avoid N+1 queries
• Use F expressions for database-level operations instead of Python
• Apply migrations atomically - one logical change per migration
• Use Django's cache framework with Redis or Memcached in production
• Write TestCase tests with assertions specific to Django (assertContains, assertRedirects)
• Use custom user models from the start (AUTH_USER_MODEL)
• Enable CSRF protection everywhere - never use @csrf_exempt without good reason
• Use environment variables for secrets - never commit SECRET_KEY or database credentials
• Deploy with Gunicorn/Uvicorn behind a reverse proxy (nginx)
• Run manage.py check --deploy before every production deployment